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<a name="gst-plugins-good-plugins-scaletempo"></a><div class="titlepage"></div>
<div class="refnamediv"><table width="100%"><tr>
<td valign="top">
<h2><span class="refentrytitle"><a name="gst-plugins-good-plugins-scaletempo.top_of_page"></a>scaletempo</span></h2>
<p>scaletempo</p>
</td>
<td class="gallery_image" valign="top" align="right"></td>
</tr></table></div>
<div class="refsect1">
<a name="gst-plugins-good-plugins-scaletempo.properties"></a><h2>Properties</h2>
<div class="informaltable"><table class="informaltable" border="0">
<colgroup>
<col width="150px" class="properties_type">
<col width="300px" class="properties_name">
<col width="200px" class="properties_flags">
</colgroup>
<tbody>
<tr>
<td class="property_type"><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gdouble"><span class="type">gdouble</span></a></td>
<td class="property_name"><a class="link" href="gst-plugins-good-plugins-scaletempo.html#GstScaletempo--overlap" title="The “overlap” property">overlap</a></td>
<td class="property_flags">Read / Write</td>
</tr>
<tr>
<td class="property_type"><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gdouble"><span class="type">gdouble</span></a></td>
<td class="property_name"><a class="link" href="gst-plugins-good-plugins-scaletempo.html#GstScaletempo--rate" title="The “rate” property">rate</a></td>
<td class="property_flags">Read</td>
</tr>
<tr>
<td class="property_type"><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#guint"><span class="type">guint</span></a></td>
<td class="property_name"><a class="link" href="gst-plugins-good-plugins-scaletempo.html#GstScaletempo--search" title="The “search” property">search</a></td>
<td class="property_flags">Read / Write</td>
</tr>
<tr>
<td class="property_type"><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#guint"><span class="type">guint</span></a></td>
<td class="property_name"><a class="link" href="gst-plugins-good-plugins-scaletempo.html#GstScaletempo--stride" title="The “stride” property">stride</a></td>
<td class="property_flags">Read / Write</td>
</tr>
</tbody>
</table></div>
</div>
<a name="GstScaletempo"></a><div class="refsect1">
<a name="gst-plugins-good-plugins-scaletempo.other"></a><h2>Types and Values</h2>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="name">
<col class="description">
</colgroup>
<tbody><tr>
<td class="datatype_keyword">struct</td>
<td class="function_name"><a class="link" href="gst-plugins-good-plugins-scaletempo.html#GstScaletempo-struct" title="struct GstScaletempo">GstScaletempo</a></td>
</tr></tbody>
</table></div>
</div>
<div class="refsect1">
<a name="gst-plugins-good-plugins-scaletempo.object-hierarchy"></a><h2>Object Hierarchy</h2>
<pre class="screen">    <a href="/usr/share/gtk-doc/html/gobject/gobject-The-Base-Object-Type.html#GObject-struct">GObject</a>
    <span class="lineart">╰──</span> <a href="/usr/share/gtk-doc/html/gobject/gobject-The-Base-Object-Type.html#GInitiallyUnowned">GInitiallyUnowned</a>
        <span class="lineart">╰──</span> <a href="/usr/share/gtk-doc/html/gstreamer-1.0/GstObject.html#GstObject-struct">GstObject</a>
            <span class="lineart">╰──</span> <a href="/usr/share/gtk-doc/html/gstreamer-1.0/GstElement.html#GstElement-struct">GstElement</a>
                <span class="lineart">╰──</span> <a href="/usr/share/gtk-doc/html/gstreamer-libs-1.0/GstBaseTransform.html#GstBaseTransform-struct">GstBaseTransform</a>
                    <span class="lineart">╰──</span> GstScaletempo
</pre>
</div>
<div class="refsect1">
<a name="gst-plugins-good-plugins-scaletempo.description"></a><h2>Description</h2>
<p>Scale tempo while maintaining pitch
(WSOLA-like technique with cross correlation)
Inspired by SoundTouch library by Olli Parviainen</p>
<p>Use Sceletempo to apply playback rates without the chipmunk effect.</p>
<div class="refsect2">
<a name="id-1.2.240.7.4"></a><h3>Example pipelines</h3>
<p>
</p>
<div class="informalexample">
  <table class="listing_frame" border="0" cellpadding="0" cellspacing="0">
    <tbody>
      <tr>
        <td class="listing_lines" align="right"><pre>1
2
3</pre></td>
        <td class="listing_code"><pre class="programlisting">filesrc location<span class="gtkdoc opt">=</span>media<span class="gtkdoc opt">.</span>ext <span class="gtkdoc opt">!</span> decodebin name<span class="gtkdoc opt">=</span>d \
    d<span class="gtkdoc opt">. !</span> queue <span class="gtkdoc opt">!</span> audioconvert <span class="gtkdoc opt">!</span> audioresample <span class="gtkdoc opt">!</span> scaletempo <span class="gtkdoc opt">!</span> audioconvert <span class="gtkdoc opt">!</span> audioresample <span class="gtkdoc opt">!</span> autoaudiosink \
    d<span class="gtkdoc opt">. !</span> queue <span class="gtkdoc opt">!</span> videoconvert <span class="gtkdoc opt">!</span> autovideosink</pre></td>
      </tr>
    </tbody>
  </table>
</div>

<p>
OR
</p>
<div class="informalexample">
  <table class="listing_frame" border="0" cellpadding="0" cellspacing="0">
    <tbody>
      <tr>
        <td class="listing_lines" align="right"><pre>1</pre></td>
        <td class="listing_code"><pre class="programlisting">playbin uri<span class="gtkdoc opt">=...</span> audio_sink<span class="gtkdoc opt">=</span><span class="string">&quot;scaletempo ! audioconvert ! audioresample ! autoaudiosink&quot;</span></pre></td>
      </tr>
    </tbody>
  </table>
</div>

<p>
When an application sends a seek event with rate != 1.0, Scaletempo applies
the rate change by scaling the tempo without scaling the pitch.

Scaletempo works by producing audio in constant sized chunks
(<a class="link" href="gst-plugins-good-plugins-scaletempo.html#GstScaletempo--stride" title="The “stride” property"><span class="type">“stride”</span></a>) but consuming chunks proportional to the playback
rate.

Scaletempo then smooths the output by blending the end of one stride with
the next (<a class="link" href="gst-plugins-good-plugins-scaletempo.html#GstScaletempo--overlap" title="The “overlap” property"><span class="type">“overlap”</span></a>).

Scaletempo smooths the overlap further by searching within the input buffer
for the best overlap position.  Scaletempo uses a statistical cross
correlation (roughly a dot-product).  Scaletempo consumes most of its CPU
cycles here. One can use the <a class="link" href="gst-plugins-good-plugins-scaletempo.html#GstScaletempo--search" title="The “search” property"><span class="type">“search”</span></a> propery to tune how far
the algoritm looks.
</p>
</div>
<div class="refsynopsisdiv">
<h2>Synopsis</h2>
<div class="refsect2">
<a name="id-1.2.240.7.5.1"></a><h3>Element Information</h3>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term">plugin</span></p></td>
<td>
            <a class="link" href="gst-plugins-good-plugins-plugin-audiofx.html#plugin-audiofx">audiofx</a>
          </td>
</tr>
<tr>
<td><p><span class="term">author</span></p></td>
<td>Rov Juvano &lt;rovjuvano@users.sourceforge.net&gt;</td>
</tr>
<tr>
<td><p><span class="term">class</span></p></td>
<td>Filter/Effect/Rate/Audio</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="id-1.2.240.7.5.2"></a><h3>Element Pads</h3>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term">name</span></p></td>
<td>sink</td>
</tr>
<tr>
<td><p><span class="term">direction</span></p></td>
<td>sink</td>
</tr>
<tr>
<td><p><span class="term">presence</span></p></td>
<td>always</td>
</tr>
<tr>
<td><p><span class="term">details</span></p></td>
<td>audio/x-raw, format=(string)F32LE, rate=(int)[ 1, 2147483647 ], channels=(int)[ 1, 2147483647 ], layout=(string)interleaved</td>
</tr>
<tr>
<td><p><span class="term"></span></p></td>
<td> audio/x-raw, format=(string)F64LE, rate=(int)[ 1, 2147483647 ], channels=(int)[ 1, 2147483647 ], layout=(string)interleaved</td>
</tr>
<tr>
<td><p><span class="term"></span></p></td>
<td> audio/x-raw, format=(string)S16LE, rate=(int)[ 1, 2147483647 ], channels=(int)[ 1, 2147483647 ], layout=(string)interleaved</td>
</tr>
</tbody>
</table></div>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term">name</span></p></td>
<td>src</td>
</tr>
<tr>
<td><p><span class="term">direction</span></p></td>
<td>source</td>
</tr>
<tr>
<td><p><span class="term">presence</span></p></td>
<td>always</td>
</tr>
<tr>
<td><p><span class="term">details</span></p></td>
<td>audio/x-raw, format=(string)F32LE, rate=(int)[ 1, 2147483647 ], channels=(int)[ 1, 2147483647 ], layout=(string)interleaved</td>
</tr>
<tr>
<td><p><span class="term"></span></p></td>
<td> audio/x-raw, format=(string)F64LE, rate=(int)[ 1, 2147483647 ], channels=(int)[ 1, 2147483647 ], layout=(string)interleaved</td>
</tr>
<tr>
<td><p><span class="term"></span></p></td>
<td> audio/x-raw, format=(string)S16LE, rate=(int)[ 1, 2147483647 ], channels=(int)[ 1, 2147483647 ], layout=(string)interleaved</td>
</tr>
</tbody>
</table></div>
</div>
</div>
</div>
<div class="refsect1">
<a name="gst-plugins-good-plugins-scaletempo.functions_details"></a><h2>Functions</h2>
<p></p>
</div>
<div class="refsect1">
<a name="gst-plugins-good-plugins-scaletempo.other_details"></a><h2>Types and Values</h2>
<div class="refsect2">
<a name="GstScaletempo-struct"></a><h3>struct GstScaletempo</h3>
<pre class="programlisting">struct GstScaletempo;</pre>
</div>
</div>
<div class="refsect1">
<a name="gst-plugins-good-plugins-scaletempo.property-details"></a><h2>Property Details</h2>
<div class="refsect2">
<a name="GstScaletempo--overlap"></a><h3>The <code class="literal">“overlap”</code> property</h3>
<pre class="programlisting">  “overlap”                  <a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gdouble"><span class="type">gdouble</span></a></pre>
<p>Percentage of stride to overlap.</p>
<p>Flags: Read / Write</p>
<p>Allowed values: [0,1]</p>
<p>Default value: 0.2</p>
</div>
<hr>
<div class="refsect2">
<a name="GstScaletempo--rate"></a><h3>The <code class="literal">“rate”</code> property</h3>
<pre class="programlisting">  “rate”                     <a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gdouble"><span class="type">gdouble</span></a></pre>
<p>Current playback rate.</p>
<p>Flags: Read</p>
<p>Allowed values: [-2.14748e+09,2.14748e+09]</p>
<p>Default value: 1</p>
</div>
<hr>
<div class="refsect2">
<a name="GstScaletempo--search"></a><h3>The <code class="literal">“search”</code> property</h3>
<pre class="programlisting">  “search”                   <a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#guint"><span class="type">guint</span></a></pre>
<p>Length in milliseconds to search for best overlap position.</p>
<p>Flags: Read / Write</p>
<p>Allowed values: &lt;= 500</p>
<p>Default value: 14</p>
</div>
<hr>
<div class="refsect2">
<a name="GstScaletempo--stride"></a><h3>The <code class="literal">“stride”</code> property</h3>
<pre class="programlisting">  “stride”                   <a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#guint"><span class="type">guint</span></a></pre>
<p>Length in milliseconds to output each stride.</p>
<p>Flags: Read / Write</p>
<p>Allowed values: [1,5000]</p>
<p>Default value: 30</p>
</div>
</div>
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